Plus IE got the box model right in the first place. It really was a good browser and had an interesting design with COM / MSHTML for embedding. The problem really was that it stagnated and had no real competition until Chrome (even though Firefox was slowly gaining traction)
Plus during this time there was little competition on the desktop market in general. iPhone and smart phones, and the Apple resurgence, was yet to come.
The problem was that they had no interest in having their browser abide by the standards that existed.
Yep, the IE 6 era felt like it lasted forever. It was a solid browser, relatively stable and fast (compared to Netscape, at least.) IE was also the main browser on Mac OS X for the first couple of releases!